Hiietam, Katrin. 2005. Case marking in Estonian grammatical relations. Leeds Working Papers in Linguistics and Phonetics 10.
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.484.8240
@article{sinnemakizeromarking-Hiietam2005, author = {Hiietam, Katrin}, journal = {Leeds Working Papers in Linguistics and Phonetics}, title = {Case marking in Estonian grammatical relations}, url = {http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.484.8240}, volume = {10}, year = {2005} }